There are a wide variety of rechargeable batteries available today for use as energy sources, including as backup energy sources. Lithium-ion batteries are one type of rechargeable battery in which lithium ions move from a negative electrode to a positive electrode during discharge and back when charging. An intercalated lithium compound is used in a lithium-ion battery as one electrode material. The electrolyte, which allows for ionic movement, and the two electrodes are constituent components of a lithium-ion battery cell. A cell is a basic electrochemical unit that contains the electrodes, separator and electrolyte. A battery or battery pack is a collection of one or more cells or cell assemblies. These may be ready for use in an electronic device by providing an appropriate housing, and electrical interconnections.
Recent events have highlighted the potential for thermal runaway events with the application of lithium-ion-technology-based batteries. For instance, lithium-ion-based batteries have the potential to experience an internal short circuit, which can lead to thermal runaway. During thermal runaway, a battery can reach temperatures of 1000° F., or more, at which point the flammable electrolyte can ignite, or even explode, when exposed to oxygen in air. Such failure incidents can be dangerous to anyone or anything nearby at the time of the event.